将不同的字符串添加到同一列表中的对象的正确方法是什么？

Question

Following example does not represent the actual class and issue, it has been adapted for various reasons.

I have a List<EnginePart> populated with objects containing byte KeyID, int Length, byte[] Value . Each object was created sequentially and has its own meaning. The list represents "parts to be replaced" and we want to output that to a sales person in a nice format, so he can tell that to the customer. Each part has its own id, lets say 0x20 - cylinder, 0x40 - oil filter.

Now i'd like to add/display a human readable string to each object in a nice way, without iterating through a foreach and checking

if(enginePart.key =="0x20") Console.WriteLine("Cylinder rotation count is " + enginePart.value) .

if(enginePart.key =="0x40") Console.WriteLine("Oil filter only filters " + enginePart.value + " of oil) .

Is there any other, nicer way to do it? Creating a new class for each engine part is not a possibility.

So far I've come up with 3 possible solutions;

1) Iterate through the list and have a bunch of ifs and WriteLines

2) Add a string to the object on creation, but in that case we still have if statements

3) Create some enum and use that on object creation

Answer 1

First I'd suggest you to override the TestClass.ToString() Method, so you won't have to build the string describing the current object in your loop.

See https://docs.microsoft.com/dotnet/api/system.object.tostring?view=netframework-4.7.2

Then maybe the 2nd solution would be quite okay, although we'd need more details on what your goal really is, or have the content of your classes.

Answer 2

Usually when you´re after a "human readable string-representation" you should overwrite ToString :

class EnginePart
{
    byte KeyID { get; set; }
    int Length { get; set; }
    byte[] Value { get; set; }

    public override string ToString()
    {
        return KeyId == "0x40" ? "Oil filter only filters " + value :
               KeyId == "0x20" ? "Cylinder rotation count is " + value :
               ...
    }
}

This way you can rely on the class´ own implementation instead of creating your own in client-code.